Exelixis Preps For Thyroid Cancer Drug Approval

Written by: Adam Feuerstein11/26/12 - 10:19 AM EST

Tickers in this article:
EXEL

SOUTH SAN FRANCISCO, Calif. ( TheStreet) -- Instead of speculating about whether or not U.S. regulators will approve Exelixis' (EXEL) drug cabozantinib for the treatment of medullary thyroid cancer later this week (we all believe approval is a layup, right?), let's instead discuss cabozantinib's potential brand names.

Personally, I like "Cabometyx," which is one of many drug brand names that Exelixis has trademarked, according to filings listed on the U.S. Patent and Trademark Office's web site.

Whichever brand name Exelixis chooses for cabozantinib, the approval isn't expected to have much of a lasting impact on the company's stock price outside of an intraday trading pop.

Exelixis shares were flat at $5.27 in early Monday trading. The FDA's approval decision on cabozantinib is expected on or before Thursday, Nov. 29.

Medullary thyroid cancer (MTC) is a rare form of thyroid cancer that is only diagnosed in about 2,800 U.S. patients each year, according to the American Cancer Society. But many MTC patients are treated surgically and therefore wouldn't require drugs like cabozantinib.

Exelixis hasn't offered specific revenue guidance for cabozantinib in MTC but management has tried to soft-pedal investor expectations about the small commercial opportunity. Analysts, who tend to over-estimate market potential, particularly before a drug is approved and launched, see peak MTC sales of about $100 million for cabozantinib.

With a market cap already approaching $1 billion, cabozantinib sales in MTC are well baked into Exelixis' stock price.

Exelixis sees the initial MTC indication for cabozantinib as only a starting point. The company's real focus is developing the drug for larger and more commercially lucrative cancer indications, most notably prostate cancer, kidney cancer and liver cancer. A twin-set of phase III studies in prostate cancer are underway with results expected in 2014.

Once cabozantinib is approved for MTC, doctors will be free to use the drug "off label" for other cancers. Exelixis cannot market or promote the drug for use in other cancers, but the company does intend to seek compendia listings for cabozantinib that will include on-label and off-label uses for the drug. Private insurance companies and Medicare use compendia listings to set reimbursement coverage for cancer drugs.

Cabozantinib is an oral drug designed to block two major molecular pathways by which tumor cells grow. In the phase III study of advanced MTC patients, treatment with cabozantinib resulted in a median progression-free survival of 11.2 months compared to 4 months for patients treated with a placebo. Cabozantinib reduced the risk of MTC re-growth by 72% compared to placebo.

In phase II studies of men with advanced prostate cancer, cabozantinib has shown the potential to reduce or halt the spread of tumors to bones as well as reduce pain.